# 素数的判断

import math
num = int(input("请输入数字："))
mid = 1
for x in range(2, int(math.sqrt(num))+1):
    if num % x == 0:
        mid = 0
        break
if mid == 1:
    print(f"{num}是素数")
else:
    print(f"{num}不是素数")